Nesostenodontus formosanus Cushman, 1937

Riedel, Matthias, 2023, Contribution to the knowledge of the Ichneumoninae (Hymenoptera, Ichneumonidae) from Maritime Southeast Asia, Zootaxa 5363 (1), pp. 1-94 : 75-77

Nesostenodontus formosanus Cushman, 1937 , new ♁

( Figs 33A–B )

Material. Indonesia: Lombok , Pusuk, c 450 m, nr Mataram, Mal. Trap 7, 21–27.iii.1991, C. van Achterberg (Leiden) .

Description. ♂. Body length 5.0 mm.

Head. Flagellum with 33 flagellomeres, bristle-shaped; 1 st flagellomere 3.7 × longer than wide. Tyloids on flagellomeres 10–15, long-oval, maximally 0.7 × as long as their flagellomeres. Temple long, slightly widened behind eye, moderately narrowed apically (fig. 33B). Occiput strongly concave. OED 2.1 × and OOD 1.3 × ocellar diameter. Vertex around stemmaticum and frons densely rugose-punctate. Face densely punctate, rugose-punctate centrally. Clypeus slightly convex; apical margin sharp and with 6 strong denticles (fig. 33A). Mandible unidentate, sickle-shaped. Malar space 0.4 × as long as width of mandibular base. Genal carina reaching mandibular base.

Mesosoma . Upper margin of pronotum bulging. Notaulus shortly impressed on frontal mesoscutum. Mesoscutum densely punctate, shining. Mesopleuron densely punctate; speculum large, smooth. Epicnemial carina low, dorsally reaching subtegular ridge. Sternaulus impressed in frontal 0.4 of mesopleuron. Metapleuron with fine sparse punctures; juxtacoxal carina absent. Scutellum moderately and roundly elevated, 1.5 × wider than long, without lateral carina. Propodeum completely carinated, without apophysis; spiracle oval. Area basalis indicated as fine median ridge (as in Imeria ). Area superomedia pentagonal, about as long as wide; costula reaching at 4/10 of its length. Area petiolaris with transverse rugae. Hind femur densely punctate, 4. 0× longer than wide. Claws simple. Areolet almost quadrangular, frontal distance between veins 2rs-m and 3rs-m 1.0 × their diameter. Vein 1cu-a interstitial.

Metasoma. Petiole long and slender. Postpetiole slightly widened, with fine sparse punctures, shining. Gastrocoelus and thyridium not impressed. 2 nd tergite 1.1 × longer than wide. 2 nd tergite densely punctate, with striated rugae in basal 2/3. 3 rd tergite with coarse dense punctures in basal half, with finer rather dense punctures apically. Following tergites with sparse fine setiferous punctures. Apical margin of hypopygium strongly rounded.

Colour. Black. Scape dorsally ivory; basal 4 flagellomeres laterally and flagellomeres 7–18 dorsally ivory. Ivory are palps, mandible except tooth, clypeus, face except brown median band, frontal orbit, outer orbit reaching up to occiput (fig. 33B), collar and hind half of upper margin of pronotum, tegula, subtegular ridge, postero-dorsal spot of mesopleuron, scutellum, metapleuron, area dentipara, petiole, apical bands of postpetiole and 2 nd tergite; posterolateral spots and narrow apical margins of 3 rd to 5 th tergites, large median spots of 6 th and 7 th tergites and paramere. Fore and mid legs except brownish distal tarsomeres ivory; hind coxa reddish, with ivory spot dorsally; hind trochanter brown; hind femur reddish, basally and apically infuscate and with dorsal ivory stripe; hind tibia reddish-yellow, basally and apically infuscate; hind tarsus ivory, base of metatarsus and distal tarsomere infuscate. Wings hyaline; pterostigma brown.

Remark. I have studied the holotype of Nesostendontus formosanus from SDEI to confirm the correlation of both sexes. The species is closely related to N. bakeri Cushman but differs mainly by smaller size, less distinctly widened upper margin of pronotum and completely carinated propodeum.

Distribution. Known from Taiwan and Myanmar, new record for Lombok.

Figures

FIGURE 33. Nesostenodontus formosanus Cushman, 1937 ♂. A face-frontal view, B head, dorsal view.